Harmonic suppression strategy based on cross-branch enhanced VSG control

The multi-node distribution station area after a large number of new energy power generation equipment is connected faces the practical problem of poor current and power quality. At the same time, the deployment of grid-connected converters dominated by virtual synchronous generator (VSG) ignores the problem of current and power quality. Therefore, in order to maintain the VSG characteristics and increase the current harmonic suppression ability, this paper proposes an enhanced VSG control strategy. Firstly, the interaction mechanism of electrical angle and voltage between AC grid and VSG in multi-VSG joint operation is analyzed. Secondly, the VSG control with cross feedback branch is proposed. This method proposes a frequency-reactive power branch and a voltage-active power branch to compensate for fluctuations without affecting the inertial characteristics of the system. Finally, the IEEE-69 network simulation distribution station area is built, and 6 VSGs are set up. The experimental results show that the enhanced VSG can provide inertial and damping support for the system. The quantitative results show that compared with the traditional VSG, the total harmonic distortion of the current is reduced by 64.2%~83.8%, which can effectively suppress the influence of the harmonics generated by the traditional VSG on the distribution network.